In triangle \( \triangle TUV \), since it is isosceles with \( \angle T \cong \angle V \), we let \( m\angle T = m\angle V = x \).
We know that the sum of the angles in a triangle is \( 180^\circ \):
\[ m\angle T + m\angle U + m\angle V = 180^\circ \]
Substituting the known values into the equation, we have:
\[ x + 54^\circ + x = 180^\circ \]
This simplifies to:
\[ 2x + 54^\circ = 180^\circ \]
Subtracting \( 54^\circ \) from both sides gives:
\[ 2x = 126^\circ \]
Dividing by 2 to solve for \( x \):
\[ x = 63^\circ \]
Thus, \( m\angle T = 63^\circ \).
So the correct response is:
m∠T = 63°.